Seeking to determine the potential dangers of pre-filled vaporizer attachments – which contain THC and/or CBD oils in a thinning agent that keeps them in liquid form for easy consumption – researchers tested four common thinning agents and found ‘notable’ amounts of cancer-causing particles in half. The fluids profiled in the study are also used in nicotine e-juice.

The researchers found that vaporizing the liquid polyethylene glycol 400 (PEG-400) produced almost four times the amount of formaldehyde of the liquid propylene glycol (PG), and 226 times that of medium-chain triglycerides (MCT) and vegetable glycerin (VG).

“The production of formaldehyde by PEG 400, in particular, may represent a significant health risk,” reads the study, “as one inhalation of vaporized PEG 400 isolate may expose an individual to as much as 1.12 percent of the daily exposure limit, nearly the same exposure as smoking one cigarette.”

Researchers also found that PEG-400 produced the most acetaldehyde – two and a half times the amount created by PG, with MCT producing less than a tenth of PG, and with VG producing less than one hundredth as much as PG.

The researchers concluded that while PG, PEG-400, and MCT all produce heightened levels of one or more carcinogens, vegetable glycerin “does not produce elevated levels of any carbonyls.”

They say more research is needed regarding the potential health concerns of vaporized products.